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<td ><a href="../qtdoc/index.html">Qt 5.12</a></td><td ><a href="qtquick-index.html">Qt Quick 模块</a></td><td ><a href="qtquick-qmlmodule.html">QML类型</a></td><td >SmoothedAnimation QML 类型</td></tr></table><table class="buildversion"><tr>
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<h3><a name="toc">目录</a></h3>
<ul>
<li class="level1"><a href="#properties">属性</a></li>
<li class="level1"><a href="#details">详细信息</a></li>
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<h1 class="title">SmoothedAnimation QML 类型</h1>
<span class="subtitle"></span>
<!-- $$$SmoothedAnimation-brief -->
<p>Allows a property to smoothly track a value. <a href="#details">更多...</a></p>
<!-- @@@SmoothedAnimation -->
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> 导入语句：</td><td class="memItemRight bottomAlign"> import QtQuick 2.12</td></tr><tr><td class="memItemLeft rightAlign topAlign">继承自：</td><td class="memItemRight bottomAlign"> <p><a href="qml-qtquick-numberanimation.html">NumberAnimation</a></p>
</td></tr></table></div><ul>
<li><a href="qml-qtquick-smoothedanimation-members.html">所有成员的列表，包括继承成员</a></li>
</ul>
<a name="properties"></a>
<h2 id="properties">属性</h2>
<ul>
<li class="fn"><b><b><a href="qml-qtquick-smoothedanimation.html#duration-prop">duration</a></b></b> : int</li>
<li class="fn"><b><b><a href="qml-qtquick-smoothedanimation.html#maximumEasingTime-prop">maximumEasingTime</a></b></b> : int</li>
<li class="fn"><b><b><a href="qml-qtquick-smoothedanimation.html#reversingMode-prop">reversingMode</a></b></b> : enumeration</li>
<li class="fn"><b><b><a href="qml-qtquick-smoothedanimation.html#velocity-prop">velocity</a></b></b> : real</li>
</ul>
<!-- $$$SmoothedAnimation-description -->
<a name="details"></a>
<h2 id="details">详细信息</h2>
<p>A <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a> animates a property's value to a set target value using an ease in/out quad easing curve. When the target value changes, the easing curves used to animate between the old and new target values are smoothly spliced together to create a smooth movement to the new target value that maintains the current velocity.</p>
<p>The follow example shows one <a href="qml-qtquick-rectangle.html">Rectangle</a> tracking the position of another using <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a>. The green rectangle's <code>x</code> and <code>y</code> values are bound to those of the red rectangle. Whenever these values change, the green rectangle smoothly animates to its new position:</p>
<pre class="qml">

  import QtQuick 2.0

  <span class="type"><a href="qml-qtquick-rectangle.html">Rectangle</a></span> {
      <span class="name">width</span>: <span class="number">800</span>; <span class="name">height</span>: <span class="number">600</span>
      <span class="name">color</span>: <span class="string">&quot;blue&quot;</span>

      <span class="type"><a href="qml-qtquick-rectangle.html">Rectangle</a></span> {
          <span class="name">width</span>: <span class="number">60</span>; <span class="name">height</span>: <span class="number">60</span>
          <span class="name">x</span>: <span class="name">rect1</span>.<span class="name">x</span> <span class="operator">-</span> <span class="number">5</span>; <span class="name">y</span>: <span class="name">rect1</span>.<span class="name">y</span> <span class="operator">-</span> <span class="number">5</span>
          <span class="name">color</span>: <span class="string">&quot;green&quot;</span>

          Behavior on <span class="name">x</span> { <span class="type"><a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a></span> { <span class="name">velocity</span>: <span class="number">200</span> } }
          Behavior on <span class="name">y</span> { <span class="type"><a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a></span> { <span class="name">velocity</span>: <span class="number">200</span> } }
      }

      <span class="type"><a href="qml-qtquick-rectangle.html">Rectangle</a></span> {
          <span class="name">id</span>: <span class="name">rect1</span>
          <span class="name">width</span>: <span class="number">50</span>; <span class="name">height</span>: <span class="number">50</span>
          <span class="name">color</span>: <span class="string">&quot;red&quot;</span>
      }

      <span class="name">focus</span>: <span class="number">true</span>
      <span class="name">Keys</span>.onRightPressed: <span class="name">rect1</span>.<span class="name">x</span> <span class="operator">=</span> <span class="name">rect1</span>.<span class="name">x</span> <span class="operator">+</span> <span class="number">100</span>
      <span class="name">Keys</span>.onLeftPressed: <span class="name">rect1</span>.<span class="name">x</span> <span class="operator">=</span> <span class="name">rect1</span>.<span class="name">x</span> <span class="operator">-</span> <span class="number">100</span>
      <span class="name">Keys</span>.onUpPressed: <span class="name">rect1</span>.<span class="name">y</span> <span class="operator">=</span> <span class="name">rect1</span>.<span class="name">y</span> <span class="operator">-</span> <span class="number">100</span>
      <span class="name">Keys</span>.onDownPressed: <span class="name">rect1</span>.<span class="name">y</span> <span class="operator">=</span> <span class="name">rect1</span>.<span class="name">y</span> <span class="operator">+</span> <span class="number">100</span>
  }

</pre>
<p>A <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a> can be configured by setting the <a href="qml-qtquick-smoothedanimation.html#velocity-prop">velocity</a> at which the animation should occur, or the <a href="qml-qtquick-smoothedanimation.html#duration-prop">duration</a> that the animation should take. If both the <a href="qml-qtquick-smoothedanimation.html#velocity-prop">velocity</a> and <a href="qml-qtquick-smoothedanimation.html#duration-prop">duration</a> are specified, the one that results in the quickest animation is chosen for each change in the target value.</p>
<p>For example, animating from 0 to 800 will take 4 seconds if a velocity of 200 is set, will take 8 seconds with a duration of 8000 set, and will take 4 seconds with both a velocity of 200 and a duration of 8000 set. Animating from 0 to 20000 will take 10 seconds if a velocity of 200 is set, will take 8 seconds with a duration of 8000 set, and will take 8 seconds with both a velocity of 200 and a duration of 8000 set.</p>
<p>The default velocity of <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a> is 200 units/second. Note that if the range of the value being animated is small, then the velocity will need to be adjusted appropriately. For example, the opacity of an item ranges from 0 - 1.0&#x2e; To enable a smooth animation in this range the velocity will need to be set to a value such as 0.5 units/second. Animating from 0 to 1.0 with a velocity of 0.5 will take 2000 ms to complete.</p>
<p>Like any other animation type, a <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a> can be applied in a number of ways, including transitions, behaviors and property value sources. The <a href="qtquick-statesanimations-animations.html">Animation and Transitions in Qt Quick</a> documentation shows a variety of methods for creating animations.</p>
<p><b>请参考</b> <a href="qml-qtquick-springanimation.html">SpringAnimation</a>，<a href="qml-qtquick-numberanimation.html">NumberAnimation</a>，<a href="qtquick-statesanimations-animations.html">Animation and Transitions in Qt Quick</a> 和 <a href="qtquick-animation-example.html">Qt Quick 示例 - Animation</a>。</p>
<!-- @@@SmoothedAnimation -->
<h2>属性文档</h2>
<!-- $$$duration -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="duration-prop">
<td class="tblQmlPropNode"><p>
<a name="duration-prop"></a><span class="name">duration</span> : <span class="type"><a href="../qtqml/qml-int.html">int</a></span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property holds the animation duration, in msecs, used when tracking the source.</p>
<p>Setting this to -1 (the default) disables the duration value.</p>
<p>If the velocity value and the duration value are both enabled, then the animation will use whichever gives the shorter duration.</p>
</div></div><!-- @@@duration -->
<br/>
<!-- $$$maximumEasingTime -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="maximumEasingTime-prop">
<td class="tblQmlPropNode"><p>
<a name="maximumEasingTime-prop"></a><span class="name">maximumEasingTime</span> : <span class="type"><a href="../qtqml/qml-int.html">int</a></span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property specifies the maximum time, in msecs, any &quot;eases&quot; during the follow should take. Setting this property causes the velocity to &quot;level out&quot; after at a time. Setting a negative value reverts to the normal mode of easing over the entire animation duration.</p>
<p>The default value is -1.</p>
</div></div><!-- @@@maximumEasingTime -->
<br/>
<!-- $$$reversingMode -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="reversingMode-prop">
<td class="tblQmlPropNode"><p>
<a name="reversingMode-prop"></a><span class="name">reversingMode</span> : <span class="type"><a href="../qtqml/qml-enumeration.html">enumeration</a></span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>Sets how the <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a> behaves if an animation direction is reversed.</p>
<p>Possible values are:</p>
<ul>
<li><a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a>.Eased (default) - the animation will smoothly decelerate, and then reverse direction</li>
<li><a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a>.Immediate - the animation will immediately begin accelerating in the reverse direction, beginning with a velocity of 0</li>
<li><a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a>.Sync - the property is immediately set to the target value</li>
</ul>
</div></div><!-- @@@reversingMode -->
<br/>
<!-- $$$velocity -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="velocity-prop">
<td class="tblQmlPropNode"><p>
<a name="velocity-prop"></a><span class="name">velocity</span> : <span class="type"><a href="../qtqml/qml-real.html">real</a></span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property holds the average velocity allowed when tracking the 'to' value.</p>
<p>The default velocity of <a href="qml-qtquick-smoothedanimation.html">SmoothedAnimation</a> is 200 units/second.</p>
<p>Setting this to -1 disables the velocity value.</p>
<p>If the velocity value and the duration value are both enabled, then the animation will use whichever gives the shorter duration.</p>
</div></div><!-- @@@velocity -->
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